Use the power method to iteratively find
the eigenvalues and eigenvectors of a real, symmetric
matrix of your choice. If you don't have an orthogonalization
routine, you can use the Gram-Schmidt program in the
file ~s244/samples/gs.c . Also extract the eigenvalues and
eigenvectors using some standard routine (NAG, EISPACK, LAPACK, etc.) and
compare the results to those from using the power method, both
numerically and with regard to execution time.